Function spawn_host_supervised 

pub(crate) fn spawn_host_supervised(
    real_exe: &Path,
    args: &[String],
    srv: &SrvSpawnResult,
    host_env: &[(&'static str, OsString)],
    pipe_path: &str,
    job_present: bool,
    job_handle: HANDLE,
    splash_event: Option<&str>,
    disable_gpu: bool,
) -> Option<Child>

Spawn the CEF host suspended, assign it to the launcher’s Job Object, and resume it. Returns the running child, or None if any step failed — the caller decides (fatal on first launch, give-up on a restart). splash_event is passed on every launch — including restarts — so a relaunched host can still dismiss a splash left pending by a host that crashed pre-first-frame. disable_gpu is the retry ladder’s rung-2 degraded mode (spec §7): when set the host is launched with --disable-gpu (software rendering).